Circuit breaker



Jan. 25, 193s.

A FJ. THOMSON cmcuzr BREAKER Original F11ed March a, 1.933

2 sums-shut 1 INVENTOR' Jan. 25, 1938.

A. J. THOMSON cmcuzr BREAKER Original Filed March 6, 1933 2 Sheets-Sheet2 Patented Jan. 25, 1938 UNITED- STATES PATENT OFFICE cnwurr BREAKER.Original application March a, 1933, Serial No.

659,714. Divided and this application January 9, 1936, Serial No. 58,438I 9 Claims. (01. 200-116) This application relates to circuit breakersand is a divisional of my prior application Serial No. 659,714, filedMarch 6, 1933.

The instant .application discloses a circuit 5 breaker having anactuating or operating mechanism to which is connected a contact and ahandle. Normally the handle is positively connected to the operatingmechanism to which is also positively connected the contact and movementof the handle positively causes movement of the mechanism and consequentmovement of the contact for manual switching.

On overload operation, the positive connection between the handle andthe mechanism is de-' stroyed automatically so that overload movement ofthe actuating mechanism and consequent movement of the contact may takeplace without the necessity for causing or being accompanied bycorresponding movement of the han- 20 die; in the instant breaker, thereis a latch which normally positively connects the handle and themechanism but which isautomaticallydisengaged by overload releasemovement of the mechanism itself to disconnect the mechanism 25 from thehandle.

While in the ordinary sense it may be considered that the handle isnormally connected to the mechanism positively and is completelydisconnected therefrom automatically on overload release movement of theparts, it may be considered that for normal operation the handle isconnected to the mechanism in such a manner that substantially no lostmotion between the handle and the mechanism exists, the operation 35 ofthe parts, however, being such that an overload release automaticallycauses a tremendous increase in the amount of lost motion between thehandle and the mechanism so that the mechanism may move free of thehandle, the 40 handle not following or accompanying the mechanism due tothe great lost motion that is automatically caused to exist between thehandle and the mechanism following overload release.

The invention is embodied in a trippable or 45 releasable latch betweenthe operating handle of a circuit breaker and the quick acting mechanismof the same, to which mechanism is con-. nected a contact. The mechanismper se and the general arrangement of the parts is substan- 50 tlallythat disclosed in my prior application Serial For an understanding ofthe herein illustrated breaker which includes the operating mechanism ofmy prior application and embodies my instant s invention,referenceshould be had to the following description and the accompanyingdrawings, in which,

Figs. 1-3a are plan, end, elevation, and diagrammatic views of abreaker, shown in on position; 1 5

Figs. 4 and 5 are elevation and end views of a group of details of themechanism thereof, in on position;

Figs. 6 and 'l are elevation views of the breaker, in ofi' and overloadof! positions, respectively; 10

Fig. 8 is an elevation view, like Fig. 4, but with the parts shown inoverload oil position.

In the drawings there is shown a breaker having the operating mechanismof my prior application and having a handle and a contact connectedthereto. Normally connecting the handle and the mechanism is a latch;this latch is automatically released on overload release movement .ofthe mechanism itself to destroy the normal operative connection betweenthe handleand the mechanism, whereupon the mechanism and its contact maymove free of the handle on overload release. 1 I

As stated above, the breaker operating mechanism in general resemblesthat of my prior application Serial No. 659,714 and has many parts whichare similar to the identically numbered parts of that breaker. Forexample, both breakers have a base ill, a warping element H, a frontplate 2|, an operating link 24, a spring 21 thereon, between pin 28, anda link 29 connected at 3| to a pawl 32 pivoted at 33, the pawl having anend 35 for engagement by tongue 36 of the warping element. The left end31 of link 24 is connected to the drum-like crank 38 by pin 39 riding 35in slot 4| of the crank, the latter having a handle 42, and beingsupported on shaft 43 connecting the front plate 2| to the back plate43a andhaving pin A riding in slot B in front plate 2|. The crankfurther has a lug 44 to engage a stop 45 on the pawl, and there is alsoprovided a pawl stop ledge 41 on a pawl stop 48.

In addition to the foregoing parts, the breaker of this case is providedwith certain novel de tails, now to be described. 45

On base Ill are contacts |l| adapted to be engaged by the bridgingcontact 2 on one end of contact arm 3, the contacts being connected tothe load and to the warping element M, respectively.

The other end of arm I i3 is enlarged and is disposed within thedrum-like bell crank 38 (Fig. 4) and is also journalled on cross shaft43.. The arm may be latched to the bell crank, so as to move therewithby a plate H5 through which passes 35 pin 39 on the end of link 24, thepin riding in a slot II! of the contact arm aligned with slot 4i of thecrank, the plate having an edge notch III in which may be disposed alatch H9, journalled by means of its lugs I29 riding in holes I2I of thedrum-like crank, and held down in notch H8 by a tension spring I22connecting the latch and a pin I23 on the contact arm H3.

The parts just described may be operated as a simple quick make andbreak switch as follows:

When handle 42 is moved to the right from on position, Figs. 3, 3a, and4, left end 39 of link 24 is moved up and to the left compressing spring21. While pin 39 is riding in slot I II of switch arm H3 and tensioningspring I22, switch arm H3 is being held by frictional engagement of thestationary contacts I H with movable contact II2.

After link 24 gets overcenter 43, spring 21 acts to complete theclockwise movement of left end 39 and handle 42. Switch arm H3, throughthe influence of spring 21 assisted by spring I22, effects a quick breakof the movable contact H2 from the stationary contacts III.

Reverse movement of handle 42 from off position, Fig. 6, causes left end39 of link 24 to move counterclockwise and to the left, tensioningspring 21 and also moving with it, contact arm H3. After link 24 movesovercenter 43, spring 27 reacts to cause quick make of'the movablecontact I I2 to the stationary contacts I I I. The positive connectionthrough the medium of the latch H9, the plate H5, and the pin 39 insurespositive make and break.

To the foregoing are added parts for moving the contact arm on overloadtrip independently of, and without requiring movement of, the handie 42,and these will now be described. In the crank 38 there is disposed aslidable plate I28 guided by, and whose slot I21 receives, the crossshaft 43. This plate has an extension I29 at one end passing through aslot I29 of the drum crank 38 and its other end is positioned to engagethe latch I I9.

The overload trip operation of these parts is as follows: When theelement I4 warps to the right, it releases pawl 32; the latter is thensnapped upwardly by spring 27. The link 24 also moves with pawl 32 aboutpin 39 as a. fulcrum. The extension I28 of plate I26 is engaged by theextension I30 of pawl 32 and is forced upward to release latch H9 fromnotch II 9, and allowing pin 39 to rotate clockwise under the combinedinfluence of springs I22 and 21 and through the movement of switch armH3, forcing movable contact H2 away from stationary contacts III toeffect a quick break of the circuit. Arm II3 moves independently ofcrank 33, for a trip free action, by virtue of the fact that pin 39 canride freely in slot 4i of the crank. Movement of crank 39 is limited bythe riding of its pin A in the slot B of the front plate 2|. Thecharacteristic that arm H3 can move independently of crank 38, so thatarm H3 can move to break the circuit even though the crank 38 is heldmanually in on position, places the breaker in the trip free class.

Excess movement of pawl 32 is prevented, not,

32, until end 35 latches under projection 34; on

overload element I4. During this movement, pin 39 rides free in slot 4I.Movement of the handle 42 also rotates latch H9 in crank 38 until italigns with slot I II in member I I 5, whereupon the spring I22 pullslatch H9 in the slot I I9, again latching member Hi, to crank member 39.Also, the resetting movement of pawl 32 frees end I29, allowing latch H9to engage slot H9.

- Contact arm H3 does not move out of the oi! position, being held inthat position through the medium of link 24 and pin 39 together withshoulder 53 of link 24 pressing against the lug 92 of link 29. The resetaction therefore places all the parts in oil position.

It will be observed that normally the handle 42 is positively conectedto the operating mechanism, with little or no lost motion between theparts through the latch I I9. On overload release movement of the parts,however, the handle is disconnected from the operating mechanism so thatthere is great lost motion between the handle and the mechanism and sothat the mechanism may move free of the handle, and such disconnectionis accomplished by raising of latch I I9 out of the notch H9 in memberH5 of the operating mechanism; this is accomplished by the engagement ofthe latch controlling part I 29 by the pawl extension I39, which pawlextension moves up on overload release of the parts to strikelatch-control member I28 and raise latch H9 out of the notch H9 inmember H5.

I claim:

1. In a circuit controller, a contact, quick acting circuit opening andclosing mechanism positively connected thereto and so constructed as tohave a normal tendency to move the contact and thus open the circuitwhen permitted so to do, holding means for the mechanism and arranged torelease it on overload and permit it to operate for circuit opening, ahandle for operating the mechanism for circuit opening or closing evenwhen the mechanism is held by the holding means, and rigid butreleasable means normally positively connecting the handle and themechanism and automatically released by overload release movement of theholding means for disconnecting the handle and the mechanism, wherebythe mechanism may operate the contact for circuit opening free of thehandle and even if the latter be held, the holding means for themechanism being separate and independent of the rigid but releasablemeans for'connecting the mechanism and the handle and also being remotefrom such rigid and releasable means.

2. In a circuitcontroller, acontact, quick acting circuit opening andclosing mechanism positively connected thereto and so constructed as tohave a normal tendency to move the contact and thus open the circuitwhen permitted so to do, holding means for the mechanism andarranged torelease it on overload and permit it to operate for circuit opening ahandle for operating the mechanism for circuit opening or closing evenwhen the mechanism is held by the holding means, and rigid butreleasable means normally positively connecting the handle and themechanism and automatically released by'the mechanism itself following amovement thereof responsive to overload release movement of theholding-means for disconnecting the handle and the mechanism, wherebythe mechanism may operate the contact for circuit opening free of thehandle and even if the latter be held, the holding means for themechanism being separate and independent of the rigid but releasablemeans for connecting the mechanism and the handle and also being remoteirom'such rigid and releasable means.

3. In a circuit controller, a contact, quick acting circuit opening andclosing mechanism positively connected thereto and so constructed as tohave a normal tendency to move the. contact and thus open the circuitwhen permitted so to do, holding means for the mechanism and arranged torelease it on overload and permit it to operate for circuit opening, alandle for operating the mechanism for circuit opening or closing evenwhen the mechanism is held by the holding means, the handle and themechanism being normally positively-connected through rigid butreleasable connecting means so that complete movement of the handlenecessarily causes circuit opening movement of the mechanism, overloadrelease of the holding means automatically releasing such releasableconnection so that circuit opening movement of the mechanism responsiveto overload release can take place free of the handle, the holding meansfor the mechanism being separate and independent of the rigid butreleasable means for connecting the mechanism and the handle and alsobeing remote from such rigid and releasable means.

4. In a circuit controller, a contact, quick acting circuit opening andclosing mechanism positively connected thereto and so constructed as tohave a normal tendency to move the contact and thus open the circuitwhen permitted so to do, holding means for the mechanism and arranged torelease it on overload and permit it to operate for circuit opening,a'handle for oper ating the mechanism for circuit. openingor closingeven when the mechanism is held by the holding means, the handle and themechanism being normally positively connected through rigid butreleasable connecting means so that complete movement of the handlenecessarily causes circuit opening movement of the mechanism, overloadrelease of the holding means automatically causing the mechanism itselfto operate for releasing such releasable connection so that circuitopening movement of the mechanism responsive to overload release cantake place free of to release it on overload and permit it to operate 4for circuit opening, a handle for operating the mechanism for circuitopening or closing even when the mechanism is held by the holding means,the handle and the mechanism being normally positively connected throughrigid but releasable connecting means so that complete movement of thehandle necessarily causes circuit opening movement of the mechanism,overload release of the holding means automatically releasing suchreleasable connection so that circuit opening movement of the mechanismresponsive to overload release can take place free of the handle, thehandle and the mechanism being normally positively connected throughrigid lost moti n means so that partial movement of" the handle does notopen the circuit through the mechanism but complete movement of thehandle does open the circuit through the mechanism,

, tion so that circuit opening through movement of the mechanismresponsive to overload release can take place even though the handle beheld.

6. In a circuitcontroller, a contact, quick acting circuit opening andclosing mechanism posito have a normal tendency to move the contact andthus open the circuit when permitted so .to

do, holding means for the mechanism and arranged to release it onoverload and P rmit it to.

handle and the mechanism being normally positively connected throughrigid lost motion means so that partial movement of the handle does notopen the circuit through the mechanism but complete movement of thehandle does open the circuit through the mechanism, overload release ofthe holding means acting through the mechanism itself for automaticallyand considerably increasing such lost motion so that circuit opening tooverload release can take place even though the handle be held.

'7. In a circuit breaker, a handle, an operating mechanism, anoverload-release latch for said mechanism and arranged to hold saidmechanism normally and to move in response to circuit conditions to freeand release said mechanism, the latter being constructed to have aninherent tendency to move out of latch-held position, which movement isinhibited normally by, the holding thereof by the overload releaselatch, means operatively connecting said mechanism to said handle, suchmeans comprising a releasable latch, separate and independent, of theoverload release latch, and arranged to normally latch the mechanism tothe handle and tobe released so as to release the handlefrom themechanism. in response to a movement'o'f the mechanism, in

through movement of the mechanism responsive turn responsive to arelease of the mechanism by overload release movement of the overloadrelease latch, whereby the mechanism can move free of the handle afterthe mechanism has caused the handle latch to be released.

8. A construction of the character of claim 5 wherein the holding meansfor the mechanism is separate and independent of the rigid butreleasable means for connecting the mechanism and the handle and alsoisremote from such rigid and releasable means.

9. A construction of the character of claim 6 wherein the holding meansfor the mechanism is separate and independent of the rigid but re-,

leasable means for connecting the mechanism and the handle and also isremote from such rigid and releasable means.

. ALFRED J. THOMSON.

10 tively connected thereto and so constructed as It 7

